1. Field
At least some example embodiments relate to a semiconductor device, a semiconductor system and a system on chip.
2. Description of the Related Art
A direct memory access (DMA) method is a data transfer method in which a controller of an input/output (I/O) device controls data transfer from a peripheral device to a main memory without executing a program using a central processing unit (CPU). The DMA method can increase the data input/output speed and can reduce a speed difference between the CPU and the peripheral device. If the input/output device requests a DMA, the CPU hands over the control of the main memory. The CPU may permit this operation whenever a cycle of the CPU is finished.
However, when updated data is to be transferred to a particular address of a system memory using a peripheral device processing unit having a built-in DMA, the existing data received from the particular address of the system memory and stored in a cache is not effective, so that the cache is first invalidated (e.g., flushed) to start a DMA function.